With the proliferation of mobile computing devices, various forms of machine-readable identifiers have become popular. Quick response (QR) codes are one type of machine-readable identifier that has become widely used. Although barcodes have been commonplace since the 1970s, the amount of data that can be practically encoded in a barcode is relatively limited. Two-dimensional barcodes, such as QR codes, greatly increase the amount of data that may be encoded. For example, QR codes may encode a uniform resource identifier (URI) such as a uniform resource locator (URL).